package com.example.demo.interceptor;

import com.example.demo.config.AppConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/*
* 登录拦截器*/
@Component
public class LoginInterceptor implements HandlerInterceptor {

    @Value("${myforum.login.url}")
    private  String defaultURL;

    /*前置处理（对请求得预处理）
    * @return true 继续流程  false 流程中断
    * @throws Exception*/
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws  Exception{
        //获取session 对象
        HttpSession session = request.getSession(false);
        //判断session 是否有效
        if(session !=null &&session.getAttribute(AppConfig.USER_SESSION)!=null){
            //用户为已登录状，效验通过
            return true;
        }
        //效验URL是否正确
        if(!defaultURL.startsWith("/")){
            defaultURL = "/" +defaultURL;
        }
        //效验不通过，跳转到登录界面
        response.sendRedirect(defaultURL);
        //中断流程
        return false;
    }
}
